The present invention relates to wireless communications systems; and, more particularly, to methods of controlling the forwarding of reverse link frames and/or information about reverse link frames in the wireless communications system.
The demand for wireless data services, such as mobile Internet, video streaming, and voice over IP (VoIP), have led to the development of high speed packet data channels to provide high data rates needed for such services. High speed packet data channels are employed on the forward link in a variety of mobile communication systems, including TIA-2000 (also known as 1xEV-DV), TIA-856 (also known as 1xEV-DO), and Wideband Code Division Multiple Access (WCDMA) systems. The high speed packet data channel is a time shared channel, with downlink transmissions, e.g., from a base station to the mobile stations, typically time-multiplexed and transmitted at full power.
In addition to receiving downlink transmissions, mobile stations transmit packet data to the base stations on what is called the reverse link. While the mobile station may be served at a given time on the downlink by a single serving radio base station, the reverse link frames transmitted by that mobile station may be received by a plurality of radio base stations, such as during soft handoff. The multiple receiving radio base stations typically forward the received frames to a call anchor node in the system for further processing, such as for outer loop power control. Thus, some measure of diversity gain may be realized on the reverse link. However, in order to achieve this diversity gain, some additional traffic is placed on the backhaul communications links internal to the system. These backhaul communications links carry information conceptually “upward” in the communications system, such as from a radio base station to its controlling base station controller, or from a non-anchor base station to a call anchor base station. For example, an Abis link between base stations may be used as a backhaul communication link, as can an Iub link between a Radio Network Controller (RNC) and a Base Transceiver Station (BTS) in a Universal Mobile Telecommunications System (UMTS) system. The additional traffic placed on the backhaul communication link(s) in forwarding the relevant frame information from multiple radio base stations to the call anchor in order to achieve the diversity gain places a burden on those backhaul link(s), which, in some instances, may negatively impact overall system performance.